<?php
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Open Software License (OSL 3.0)
 * that is bundled with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/osl-3.0.php
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@magentocommerce.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magentocommerce.com for more information.
 *
 * @category    Mage
 * @package     Mage_Catalog
 * @copyright   Copyright (c) 2012 Magento Inc. (http://www.magentocommerce.com)
 * @license     http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */


/**
 * Catalog Layer Attribute Filter Resource Model
 *
 * @category    Mage
 * @package     Mage_Catalog
 * @author      Magento Core Team <core@magentocommerce.com>
 */
class Mage_Catalog_Model_Resource_Layer_Filter_Attribute extends Mage_Core_Model_Resource_Db_Abstract
{
    /**
     * Initialize connection and define main table name
     *
     */
    protected function _construct()
    {
        $this->_init('catalog/product_index_eav', 'entity_id');
    }

    /**
     * Apply attribute filter to product collection
     *
     * @param Mage_Catalog_Model_Layer_Filter_Attribute $filter
     * @param int $value
     * @return Mage_Catalog_Model_Resource_Layer_Filter_Attribute
     */
    public function applyFilterToCollection($filter, $value)
    {
        $collection = $filter->getLayer()->getProductCollection();
        $attribute  = $filter->getAttributeModel();
        $connection = $this->_getReadAdapter();
        $tableAlias = $attribute->getAttributeCode() . '_idx';
        $conditions = array(
            "{$tableAlias}.entity_id = e.entity_id",
            $connection->quoteInto("{$tableAlias}.attribute_id = ?", $attribute->getAttributeId()),
            $connection->quoteInto("{$tableAlias}.store_id = ?", $collection->getStoreId()),
            $connection->quoteInto("{$tableAlias}.value = ?", $value)
        );

        $collection->getSelect()->join(
            array($tableAlias => $this->getMainTable()),
            implode(' AND ', $conditions),
            array()
        );

        return $this;
    }

    /**
     * Retrieve array with products counts per attribute option
     *
     * @param Mage_Catalog_Model_Layer_Filter_Attribute $filter
     * @return array
     */
    public function getCount($filter)
    {
        // clone select from collection with filters
        $select = clone $filter->getLayer()->getProductCollection()->getSelect();
        // reset columns, order and limitation conditions
        $select->reset(Zend_Db_Select::COLUMNS);
        $select->reset(Zend_Db_Select::ORDER);
        $select->reset(Zend_Db_Select::LIMIT_COUNT);
        $select->reset(Zend_Db_Select::LIMIT_OFFSET);

        $connection = $this->_getReadAdapter();
        $attribute  = $filter->getAttributeModel();
        $tableAlias = sprintf('%s_idx', $attribute->getAttributeCode());
        $conditions = array(
            "{$tableAlias}.entity_id = e.entity_id",
            $connection->quoteInto("{$tableAlias}.attribute_id = ?", $attribute->getAttributeId()),
            $connection->quoteInto("{$tableAlias}.store_id = ?", $filter->getStoreId()),
        );

        $select
            ->join(
                array($tableAlias => $this->getMainTable()),
                join(' AND ', $conditions),
                array('value', 'count' => new Zend_Db_Expr("COUNT({$tableAlias}.entity_id)")))
            ->group("{$tableAlias}.value");

        return $connection->fetchPairs($select);
    }
}
